1. Field of the Invention
The present invention relates to various paper office supplies and, in particular, to those paper office supplies having reinforcement layers disposed along surfaces that are susceptible to premature wear and tear to make the office supplies stronger and more durable.
2. Description of the Prior Art
Paper office supplies are widely used by businesses and students to store, maintain and present documents. These supplies, herein generally referred to as folders, include hanging jackets or files, folders, shelf files, file jackets, report covers, portfolios, folder dividers, and binders. As widespread and popular as these folders are, however, they each suffer from the problem of premature wear and tear along certain critical areas. These areas include fold creases, areas that are frequently handled by office workers, areas that rub against other items such as file cabinets, and areas which are frequently subjected to pulling forces, such as the pockets in a folder.
These durability problems were surprising because extensive material tests are conducted in laboratories on characteristics such as tear strength, burst strength, and fold endurance of folders. It was estimated that in a normal to heavy use environment, the useful life of folders would be from 7 to 15 years.
In investigating this problem, it was found that there are several different factors that contribute to this premature wear and tear. A first factor is that skin oils and acids from the fingers of office workers are transferred to the folders while they are being handled. These oils and acids, coupled with constant abrasion from touching, weakens the paper in the folder and makes it susceptible to failing.
A second factor is that the folders are often overstuffed, thereby subjecting the folder to excessive weight and stress. This excessive weight and stress concentrates on the fold corners and points of intersection of different surfaces of the folders, and will cause the folder to fail at these locations.
Finally, the folders are often mishandled by the office workers who either drop them into file cabinets or onto work surfaces. This further weakens the folder at stress points such as corners and seams and will cause the folder to eventually burst or split.
This problem of premature wear and tear was not previously brought to the attention of those skilled in the art, because such folders are frequently discarded immediately after the premature failure is discovered.
A number of possible solutions are available and were contemplated to eliminate this problem. These solutions include using thicker weight paper or paper reinforcements in the folder, impregnating the paper with plastic, or making the folder entirely out of plastic. However, each of these solutions were rejected because of manufacturing and cost constraints.
Accordingly, there remains a need for a folder of superior strength that is durable, may be manufactured inexpensively, and that is not susceptible to premature wear and tear.